Soon enough, others are seeing strange apparitions: Sulu finds a pistol lying on the ground; Kirk sees Finnegan, the upperclassman who tormented him at the Academy; the legendary Don Juan appears to YeomanTonia Barrows. These are not figments; they are real objects. And then Kirk meets Ruth, an old flame, exactly as she was fifteen years ago.

Spock calls from the ship. He has detected an energy field on the surface of the planet – one that is draining the Enterprise's power. The patterns are consistent with industrial activity, perhaps subterranean. Communications are fuzzy and intermittent, and more dangerous things begin appearing: a tiger, a samurai warrior, and an ancient fighter plane performing a strafing run. Spock manages to beam down after communications fail completely; and he's the last; the transporter is also inoperative. The planetary field soaks up energy at the source.

Kirk instructs the landing party to rendezvous at the beam down point at the glade; there, McCoy encounters a black knight. Convinced it cannot harm him, he stands his ground – and takes a lance through the chest, dying instantly.

The landing party are stunned by McCoy's death, but have to stay on alert because they have to be prepared for anything. Meanwhile after Spock discovers that the black knight wasn't real, McCoy's body disappears. Spock then comes to the conclusion that these artifacts can be as real as they are deadly. Just as the Vulcan asks Kirk what was he thinking at the time, Finnegan reappears. Kirk goes after him personally wanting to find out what has been happening to his people. Finnegan beats up Kirk and they get into a fight. When Kirk gets the best of Finnegan, the former cadet fakes a back injury, and when Kirk tries to help him up, Finnegan flips Kirk over, knocking the captain out.

But beating the tar out of Finnegan makes up for a lot of past miseries, a fact that Spock finds enlightening. He and Kirk realize the truth: all of the artifacts are representations of someone's wish fulfillment fantasy. Gathering the landing party, he instructs them to remain at attention, and not to think of anything.

An elderly man appears; this caretaker confirms the guess: his people constructed this planet as a playground. Anything one can think of can be manufactured – and none of it is permanent. McCoy, taken below, has been completely healed, and as a bonus has a chorus girl from a cabaret on Rigel II on each arm. The caretaker offers the use of the Shore Leave Planet to the crew while cautioning them to take care what they summon. He will not comment on his species or their home planet, saying enigmatically that he believes the Enterprise crew are not yet ready to understand his people. Kirk plans to beam down shore parties, and beam himself back to the ship... and then Ruth reappears, changing his mind.

"Captain's log, stardate 3025... uh, .3. We are orbiting an uninhabited planet in the Omicron Delta region, a planet remarkably like Earth or how we remember Earth to be: park-like, beautiful, green, flowers, trees, green lawn, quiet and restful. Almost too good to be true."

"Captain's log, stardate 3025.8. Investigation of this increasingly unusual planet continues, and we are seeing things that cannot possibly exist, yet they are undeniably real."

Much of this episode was being rewritten as it was being shot. Cast members recalled executive producer Roddenberry sitting under a tree, frantically reworking the script to keep it both under budget and within the realms of believability. (The Star Trek Compendium, p. 49) As a result the filming of this episode went over schedule and resulted in seven shooting days instead of the usual six. [1]

Roddenberry deemed Theodore Sturgeon's original script too much fantasy, and lacking believability. Gene L. Coon was assigned to re-write it, however he misinterpreted the task and his draft turned out to be even more of pure fantasy. Roddenberry then began to heavily re-write the script, but since they had run out of time, he had to do it subsequently with the filming of the episode.[2]

Editor Fabien Tordjmann came up with the idea of having Finnegan continue to pop out of nowhere as Kirk pursues him. This gave the impression that there was more than one Finnegan or, at least, that he was not quite human.

The preview of this episode shows Yeoman Barrows being accosted by Don Juan while wearing her princess costume. This scene was not used in the final cut.

The writer of this episode, Theodore Sturgeon, commented about the installment, "That was a gas because anything could happen. Any wild idea you could possibly have could be stuck into that script. Everybody had a good time with that one." [3] Sturgeon submitted a story outline for a sequel to this episode, "Shore Leave II", in April 1968 but it was not produced. It is unknown whether any of the concepts from that outline were later worked into TAS: "Once Upon a Planet".

This was composer Gerald Fried's first Star Trek assignment. A great deal of new music was written for this episode, including the jig that plays whenever Finnegan appears. The flute and string piece that is played when Kirk meets Ruth is heard again in "This Side of Paradise", and a slightly different orchestration crops up in "The Apple". A snatch of Finnegan's jig can be heard in "The City on the Edge of Forever" after Kirk and Spock escape from the policeman. The theme can also be heard in "Wolf in the Fold".

The "wind chime" planet sound effect heard here is unique to this episode.

As in "Arena", the shore leave planet is an Earth globe (previously seen in "Miri") printed backwards with exotic colors added. This is the first of two episodes in which the ship is shown orbiting right to left. It is actually just printed backwards, as the numbers on the nacelles are reversed. The second instance, and only in the teaser, is "Mirror, Mirror".

Normally, the series' closing credits featured a random assortment of screen grabs from a variety of episodes. But the closing credits of "Shore Leave" included five scenes from the episode: 1) The Enterprise orbiting the shore leave planet, 2) Finnegan shouting from atop Vazquez Rocks, 3) Kirk pursuing him, 4) the glade, and 5) the Black Knight.

According to Herb Solow and Robert Justman's book Inside Star Trek: The Real Story, director Robert Sparr did an excellent job on this episode, and successfully managed to direct it simultaneously with the shooting script being written. However, the cast disliked working with him, which resulted in this episode being his only Trek assignment. According to Justman, the challenging task of directing the complicated episode literally hours after the script arrived, made Sparr not concentrating enough on the actors, hurting their egos. Justman tried to bring Sparr back to the series in the second season, but it didn't come to fruition.

Unique to this episode, the handles of the phaser pistols are painted black.

Paint was also applied to some of the rocks and trees, which have been doctored with streaks of red spray paint, presumably to make them look more exotic. This technique can also be seen in "A Private Little War". (The Star Trek Compendium, p. 49)

A chained tiger is brought in to appear in the episode. While the tiger never directly interacts with any of the performers, William Shatner had originally hoped to wrestle it, but was convinced it would not be a wise decision. (The Making of Star Trek, p. 306)

There were also plans for an elephant to appear in this episode but they never materialized. [5] Later, production staff members often jokingly asked assistant director Gregg Peters, "Say - when do you get to use your elephant?" (The Making of Star Trek, p. 305)

The World War II fighter plane sequence is depicted by recycled footage of several different plane types. When it is first seen in the distance it appears to be a USMC Corsair with its gull wing configuration and markings. When the plane comes in closer for a ground attack it appears to be the front of a P-47 Thunderbolt. A second plane flying in formation can be seen in that shot. Finally, for the closeups of cockpit and wing section, it appears to be a Japanese Zero along with Imperial Japanese aircraft markings.

William Blackburn (a professional ice skater in real life), who played the White Rabbit, got the costume from Ice Capades for free. The claustrophobic Blackburn had a really painful time wearing it, especially as costume designer William Ware Theiss had originally sewn the Rabbit head to the suit. After nearly suffocating, Blackburn tore off the head, for which Theiss became very mad at him. Finally, they negotiated and Theiss put the head back with Velcro. Afterwards, Blackburn had no problem with the costume. He also commented that wearing the Gorn head in "Arena" was "even worse." [6]

Although Kirk appears to address the "Angela" character as "Teller" early in the episode, she is played by Barbara Baldavin, who played Angela "Martine" in "Balance of Terror" (her fiancé, Robert Tomlinson, died in the episode). The script name for her character was "Mary Teller" and was changed to Angela Martine on the set when somebody noticed Barbara Baldavin already appeared as a named character. In the closing credits, she is identified as "Angela". (The Star Trek Compendium, p. 49)

The original script featured YeomanRand as part of the landing party, but as the character was written out of the series, she was changed to YeomanTonia Barrows. Also, in Sturgeon's original script, the Yeoman had a share of close scenes with Kirk. In the rewrites, Coon and Roddenberry changed these to feature Doctor McCoy instead and introduced Kirk's old Academy flame Ruth to the story. (These Are the Voyages: TOS Season One)

According to interviews with Bill Blackburn, he not only voiced the White Rabbit, but also did the announcements heard in Act One dismissing different sections of the ship for shore leave in alphabetical order. (TOS Season 1 HD DVD, special features)

Mystery Science Theater 3000 paid tribute to "Shore Leave" in their episode "The Thing That Couldn't Die." In the third host segment, the Observers thought they were bringing people from Mike Nelson's past to visit him, but the first person they brought back was Finnegan. Accompanied by a version of his music, Finnegan tormented and beat up Mike.

The remastered version of "Shore Leave" aired in many North American markets during the weekend of 26 May2007. While the episode required very few new effects, the Shore Leave Planet was given a CGI-makeover, now a more Earth-like planet resembling its appearance in TAS: "Once Upon a Planet", rather than the nearly amorphous green blob of the original episode. [7]